1. Field of the Invention
This invention relates to a lubricant comprising an adduct of melamine and isocyanuric acid or cyanuric acid. While solid lubricants commonly used in practice are inorganic compounds or organic polymers, the adduct of melamine and (iso)cyanuric acid according to this invention is characterized as an organic salt, and its lubricating performance has not been appreciated. The lubricant prepared according to this invention effectively prevents seizures or minimizes wear to a degree that has not been possible with conventional lube oils, in particular it is able to minimize wear under extremely high pressures to a higher degree than the conventional solid lubricants.
2. Description of the Prior Art
Lubricants are classified by form into solid lubricants, liquid lube oils and semisolid grease.
Solid lubricants are applied in high-temperature, low-temperature or high-pressure uses where lube oils cannot effectively be used, or in food processing machines in which the odor of lube oils is not tolerable. Conventional solid lubricants include molybdenum disulfide, tungsten disulfide, colloidal graphite, barium oxide and zinc oxide powder having crystalline structure, or sodium borate, lead oxide and zinc monoxide powder having noncrystalline structure, all of them are inorganic compounds. Examples of an organic solid lubricant are polymers such as polytetrafluoroethylene. Solid lubricants may be used per se but more often than not they are blended with oils into a paste form or incorporated in a lube oil or grease composed of a mineral oil blended with a metal soap.
Molybdenum disulfide and colloidal graphite which are common high-performance solid lubricants are not advantageous. They are expensive and when they are used independently as a solid lubricant, molybdenum disulfide is oxidized at high temperature to produce molybdenum oxide which is so abrasive that the resulting wear is more excessive than without lubrication. Furthermore, when mixed with lube oil or grease these solids provide a dark product with low commercial value and therefore limited utility is produced. Due to their high specific gravity, molybdenum disulfide and colloidal graphite cannot be stably dispersed in a solvent or water without specially sophisticated technology.
While a melamine/cyanuric acid adduct has been used as an opacifier in products such as liquid detergents, lotions, shampoos and the like, as disclosed in U.S. Pat. No. 3,532,635, its use as a lubricant has not been recognized.